Corsican nationalist Yvan Colonna is seen in this document released by the French Interior Ministry May 25, 1999.  French Interior Ministry/Handout via
Corsican nationalist Yvan Colonna is seen in this document released by the French Interior Ministry May 25, 1999. French Interior Ministry/Handout via Reuters / FRENCH INTERIOR MINISTRY

French President Emmanuel Macron on Tuesday called for calm after the death of jailed Corsican separatist militant Yvan Colonna, whose assault by a fellow inmate triggered violent protests on the French Mediterranean island earlier this month.

Colonna, who was serving a life sentence for the killing of a senior official in Corsica in 1998, had been in a coma since he was strangled on March 2 by a fellow inmate whom French Interior Minister Gerald Darmanin subsequently described as a "radicalised, Islamist terrorist".

After the attack on Colonna, protesters clashed with police and attacked public buildings in Corsica. The death of 61-year-old Colonna on Monday in a Marseille hospital has raised fears of more violence.

"The most important thing is that the calm is maintained, that talks continue," Macron said in an interview with France Bleu radio, praising local politicians for making similar appeals.

The protests prompted an emergency visit by Darmanin, who said Paris could discuss autonomy for Corsica.

The island has a history of separatist violence and the government is set to keep a close eye on any signs of a flare-up as France prepares for the first round of a presidential election on April 10.

Prosecutors started a terrorism investigation into Colonna's strangling at the prison. The other inmate was jailed in 2016 for nine years on terrorism-related charges, according to France's anti-terrorism prosecutor's office.

Macron said action would be taken "because we cannot allow these kinds of acts to happen in our prisons".

Colonna, a shepherd, was serving a life sentence at a prison in the southern French city of Arles for the 1998 murder of Claude Erignac, who as prefect of Corsica embodied the power of the French state on the island. He said he was innocent.

Mourners peacefully gathered in two Corsican towns to pay respects to Colonna on Monday evening, local media reported.

Roger Antech, editor-in-chief of newspaper Corse Matin, told FranceInfo radio that he felt the situation would calm down out of respect for Colonna's family until his burial, but there was "no guarantee as to what happens afterwards."

The protests earlier this month were partly fuelled by anger that Corsican separatists like Colonna have to serve out their prison sentences in mainland France, rather than on the island.

French Prime Minister Jean Castex said in a statement that two other Corsican prisoners - Alain Ferrandi and Pierre Alessandri - will be allowed to serve out their sentence in Corsica. He said they will be transferred by mid-April.

Marine Le Pen, the far-right leader who could make it into the second round of presidential elections, said the government owed voters answers on how such a "shameful" death could have happened.